Dry cell



W. BALDERSTON.

DRY CELL.

APPLICATION FILED oc.3.

IQIQ.

Patented May 31, 1921.

UNI ED STATES PATENT OFFICE.

mum mn, or mmson, WISCONSIN, assrcnoa 'ro ranncn BATTERY .2

,GQBBQH or mison, WISCONSIN, a coaromnon or .WISGONSDT.

Dar can.

Specification of Letters Patent.

Patented May 31, 1921.

Application filed December 3, 1919- Serial No. 842,089.

ful Improvement in Dry Cells, of which the following is a specification.

The present invention is in the nature of an improvement in dry cells; and the pmmar object is to provide a dry cell, especial y of the type employed for use in flashlights, which can be more cheaply manufactured and which will operate more satisfactorily than dry cells as at present constructed. a

The invention is illustrated in itspreferred embodiment in the accompanying drawing, in which- Fi re 1 represents a sectional view of a flashight containin two cells constructed in accordance with t e invention; Fig. 2, a sectional view of one of the cells shown in Fig. 1; and Fig. 3, a broken sectional viewshowing the upper ortiofi of a known construction of cell an illustrating the difiiculties experienced in the use of such cells.

Referring to Figs. land 2, Arepresents a flash-lightcasing eguipggd with a circuit- .c'losing device A, an E, dry cells adapt- 90 ed for use in said flash-light Each cell B com rises a zinc casing 1 having its upper and closed bysealing material 2; a compacted core 0 o depolarizing mixture, usually com rising manganese SIS dioxidand owdered car onaceous material;

and. a car on electrode D, preferably of circular cross-section, the lower ortion of which is embedded in the core and the up or end-portion of which is embedded in 40 an rojects slightly above the sealing ma- .teria .2. The annular space between the zinc container 1 and the core 0 is filled with a suitable electrolyte E, usually consisting of ammonium chlorid, zin'c ch 46 and starch, the starch being gelatinized, so that the electrolyte is in the form of a paste,

or jelly-like mass. It is usual to insert a disk, or washer, 3 inthe upper portion of the container upon which the sealing matolterial, or pitch, may be oured in sealing the upper end of the can. It is usual, also,

to leave a space 4 in the container to permit the necessary ex ansion of the electrolyte and to accommo ate any gases which may 66 be formed. It may be stated, however, that orid, water as the dry-cellscontinue to operate, some of the electrolyte is liable to ooze or be forced East the pitch 2. To prevent injury to the ry cell as a result thereof, the u or end-.

portion of the carbon electrode is left naked, or uncovered. That is, the naked upper end-portion of the carbon electrode i is embedded in the sealing material 2 and projects slightly above the upper surface thereof, thus presentin at the end surface of the carbon a nake carbon surface, or contact abutment, 5. Usually, the contact pro ects from aneighth of an inch to a quarter of an inch above the sealing material 2.

Fig.3 represents the common method of capping the carbon electrode in this typeof battery with a brass or co per cap 6. Otherwise, the cell, desi at B, is constructed in the manner scribed, and the same reference characters are employed to ndicate the parts. Heretofore in constructing dry .cells of this type, it has been regarded as necessary and has been the practice to employ a brass cap on the upper end of the carbon electrode, for the supposed purpose of preserving the electrode from disintegration and giving, a, good contact surface. In practice, however, some of the electrolyte escapes past the seal 2 and attacks the brass cap 6, thereb forming a scale of metal oxid and electrol yte 6, which is reflected across, or partially across, the

upper surface of the pitch seal 2. The effect is to greatly injure the contact and to tend to. cause leakage, or a 'partial short circuit,

from the upper end of the carbon electrode to the zinc can. Thus, not only is the elficiency of the cell lowered and its life shortened, but the contact is injured or rendered less conductive, so that the best results are not obtained with flash-lights employing such construction. It is found that in some cases the upper wall of-the brass cap 6 is almost entire eaten away and isrel-placed b oxid and erhaps some of the electrol NZ) is T zinc can of the upper cell rests u on the naked carbon surface of the carbon electrode of the 11 per cell, and the contact at the inner end of the shank of the lamp-bulb rests upon the naked carbon surface of the 'th electrode D of the upper cell. It is found in, practice that the naked carbon surface affords a perfectly good contact, and that the contact will not become coated or incrusbed' with any materials-which tend to injure or destroy the contact or lessen the conductivity thereof. Moreover, the tendency of a scale to form acrom the upper surface of the cell 2 is greatly lessened, and the tendency, therefore, is to prolong the life-of the cell.

The foregoing detailed description has been given for clearness of understanding only, and no unnecessary limitation should be understood therefrom, but the appended claims should be construed as broadly as permissible, in view of the prior art.

thereof, a core of depolanzi said container and a carbon .bedded in said core and having a naked ing sli WhatI re rd as new and desire to aecure by Letters atent is: a

1. A dry cell comprising a container having sealing material closing the upper end ereof, a core of depolarlzing mixture in said container, electro and container, and a carbon electrode embedded in said core and extending through said sealing material and having a naked carbon end surface ex osed as an abutment contact above said sealing material.

2. A dry cell comprising a container having sealing material closing the vupper end mlxture in e ectrode -em upper end portion embedded in and projecthtly above the said sealing material,

yte between said core the en surface of said electrode serving as 40 a non-corrodible abutment contact.

WILLIAM BALDERSTON. 

